Amitriptyline constipation with

Despite limited success with amitriptyline in some anorexia patients, using this class of antidepressants can be problematic in AN patients and therefore cannot be routinely recommended. TCAs slow gastrointestinal function and can therefore worsen the constipation and bloating that commonly plague AN patients during refeeding. In addition, TCAs can increase the likelihood of seizure or cardiac arrhythmia in patients already at risk due to electrolyte disturbances. Moreover, they are often lethal after overdose. 

When treating insomnia without depression, doxepin and amitriptyline (both tricyclic antidepressants) can be administered in low doses (25-100 mg) at bedtime. These antidepressants, however, do have troublesome anticholinergic side effects (dry mouth, constipation, blurred vision, dizziness) and adverse effects on the heart, and they can be lethal if taken in overdose. Because of their effect on heart function, these antidepressants should be avoided in patients with heart problems and administered cautiously, if at all, to those who are already receiving one of any number of newer antidepressants that inhibit the metabolism of the TCAs. 

The primary adverse effects of TCAs have been described in the previous text. Anticholinergic effects are perhaps the most common. These effects result in dry mouth, constipation, urinary retention, blurred vision, and confusion. They are more common with tertiary amine TCAs such as amitriptyline and imipramine than with the secondary amine TCAs desipramine and nortriptyline. The potent a-blocking property of TCAs often results in orthostatic hypotension. Hi... 

If diarrhea is the chief complaint, it is treated with loperamide or cholestyramine. Pain is treated with dicyclomine, amitriptyline, and peppermint oil. Bran and psyllium are used to treat the constipation that may occur in IBS. Elatnlence is treated with simethicone. 

The interactions with cimetidine are well established, well documented and of clinical importance. The incidence is uncertain hut most patients could be affected. Those taking amitriptyline, desipramine, doxepin, imi-pramine or nortriptyline who are given cimetidine should be warned that adverse effects such as mouth dryness, urine retention, blurred vision, constipation, tachycardia, postural hypotension may be more likely to occur. Other tricyclic antidepressants would be expected to be similarly affected. If symptoms are troublesome reduce the dosage of the antidepressant (33 to 50% has been suggested) or replace the cimetidine with ranitidine, which does not appear to interact. Other H2-ieceptor antagonists that do not cause enzyme inhibition (e.g. famotidine and nizatidine) would also not be expected to interact. 

Surgical acute pain amitriptyline may be beneficial for adjunctive use for pain control as well as nighttime sedation. Patients recovering from amputation, traumatic or surgical nerve injuries (intercostal nerves, branches of the brachial plexus, inguinal and genitofemoral nerve, etc.). Consider starting dose of 12.5-25 mg qhs and increase to 50 mg as tolerated. Monitor for urinary retention/constipation that may coincide with post-operative symptoms. Consider nortriptyline or desipramine to reduce side effects. 

---